U.S. patent number 8,702,036 [Application Number 13/317,493] was granted by the patent office on 2014-04-22 for system for overhead storage of cargo containers in upper lobe of aircraft.
The grantee listed for this patent is James M. Curry, Randolph Schemkes. Invention is credited to James M. Curry, Randolph Schemkes.
United States Patent |
8,702,036 |
Curry , et al. |
April 22, 2014 |
System for overhead storage of cargo containers in upper lobe of
aircraft
Abstract
A cargo storage and handling system for aircraft. A rack
assembly mounts in an upper portion of the fuselage to form a cargo
area in the upper lobe thereof. The rack includes a series of
frames that are suspended from pre-existing attachment points for
luggage bins. Cargo rails mounted on the frames support containers
for movement through the upper lobe cargo area. Cargo may be raised
to the upper lobe cargo area from the main deck of the aircraft
using a lift apparatus. The lift apparatus includes a platform that
is raised/lowered by a lift mechanism, the lift mechanism being
mounted to/or enclosed within a barrier between the cargo and
personnel areas of the aircraft, such as a 9G Barrier. A cover
apparatus closes a cargo hole in the main deck of the aircraft for
personnel safety. The cover apparatus includes a plurality of the
elongate plate members that are mounted to underfloor portions of
the seat tracks of the main deck of the aircraft so as to be
selectively extensible/retractable into and out of the opening.
Inventors: |
Curry; James M. (Lake Stevens,
WA), Schemkes; Randolph (Snohomish, WA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Curry; James M.
Schemkes; Randolph |
Lake Stevens
Snohomish |
WA
WA |
US
US |
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Family
ID: |
44906354 |
Appl.
No.: |
13/317,493 |
Filed: |
October 18, 2011 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20120160961 A1 |
Jun 28, 2012 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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61455369 |
Oct 18, 2010 |
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61458756 |
Nov 30, 2010 |
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Current U.S.
Class: |
244/118.1;
244/118.5; 244/119 |
Current CPC
Class: |
B64C
1/20 (20130101); B64D 9/00 (20130101); Y02T
50/40 (20130101) |
Current International
Class: |
B64C
1/22 (20060101) |
Field of
Search: |
;244/118.1,118.5,118.2,118.6,119,137.1,137.2 ;198/465.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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3501887 |
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Jan 1985 |
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DE |
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1 211 174 |
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Jun 2002 |
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EP |
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WO95/23733 |
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Sep 1995 |
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WO |
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Primary Examiner: Ellis; Christopher P
Assistant Examiner: Badawi; Medhat
Attorney, Agent or Firm: Hathaway; Todd N.
Parent Case Text
RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Patent
Application Ser. No. 61/455,369 filed on 18 Oct. 2010 and U.S.
Provisional Patent Application Ser. No. 61/458,756 filed on 30 Nov.
2010.
Claims
What is claimed is:
1. An apparatus for carrying cargo in an aircraft, said apparatus
comprising: a rack assembly mounted in an upper part of a fuselage
of said aircraft so as to define a cargo area in an upper lobe
thereof, said rack assembly comprising: a plurality of transverse
rack frames mounted at intervals to frames of said fuselage of said
aircraft, said transverse rack frames each comprising: a lower
frame member that extends substantially horizontally across a lower
side of said cargo area; first and second suspension frame members
that extend generally upwardly from said horizontal frame member
towards locations on said frames of said fuselage from which said
rack assembly is suspended; crossbeam members mounted to said upper
ends of said suspension frame members and having upper and lower
ends; and pivotable link members interconnecting said upper and
lower ends of said crossbeam members to said frames of said
fuselage so as to support said upwardly extending suspension frame
members of said rack frames from said frames of said fuselage, said
pivotable link members being aligned to transmit loads from said
frame of said rack assembly to said frame of said fuselage in a
generally radial direction; and at least one lengthwise member that
supports a plurality of cargo containers arranged longitudinally on
said rack assembly within said cargo area in said upper lobe of
said aircraft.
2. The apparatus of claim 1, wherein said locations on said frames
of said fuselage from which said rack assembly is suspended
comprise: pre-existing luggage bin attachment points on said frames
of said fuselage.
3. The apparatus of claim 1, wherein said at least one lengthwise
member that supports said plurality of cargo containers arranged
longitudinally on said rack assembly comprises: at least one cargo
rail extending generally longitudinally across a plurality of said
lower frame members of a plurality of said rack frames.
4. The apparatus of claim 1, wherein said rack assembly further
comprises: at least one substantially horizontal panel member
mounted to said lower frame members of said plurality of rack
frames so as to form a shear panel for said rack assembly.
5. The apparatus of claim 1, further comprising: a deflection
control assembly that maintains said fuselage against distortion by
said rack assembly.
6. The apparatus of claim 5, wherein said deflection control
assembly comprises: at least one rigid member mounted transversely
across an upper end of said frame of said fuselage above said
storage area of said rack assembly so as to hold said frame against
bowing inwardly under loads exerted by said rack assembly; and at
least one tension member interconnecting each of said upwardly
extending suspension frame members to said frame of said fuselage
so as to hold said frame from bowing outwardly under loads exerted
by said rack assembly.
7. The apparatus of claim 6, wherein said at least one rigid member
mounted transversely across an upper end of said frame above said
storage area of said rack assembly comprises: at least one rigid
spreader bar member.
8. The apparatus of claim 6, wherein said at least one tension
member interconnecting each of said upwardly extending suspension
beam members to said frame of said fuselage comprises: at least one
flexible tension cable.
9. The apparatus of claim 1, wherein said rack assembly extends
substantially a full length of a main fuselage section of said
aircraft.
10. An apparatus for carrying cargo in an aircraft, said apparatus
comprising: a rack assembly mounted in an upper part of a fuselage
of said aircraft so as to define a cargo area in an upper lobe
thereof, said rack assembly comprising: a plurality of transverse
rack frames mounted at intervals to frames of said fuselage of said
aircraft, said transverse rack frames each comprising: a lower
frame member that extends substantially horizontally across a lower
side of said cargo area; first and second suspension frame members
that extend generally upwardly from said horizontal frame member
towards locations on said frames of said fuselage from which said
rack assembly is suspended; and a deflection control assembly that
maintains said fuselage against distortion by said rack assembly,
said deflection control assembly comprising: at least one rigid
member mounted transversely across an upper end of said frame of
said fuselage above said storage area of said rack assembly so as
to hold said frame against bowing inwardly under loads exerted by
said rack assembly; and at least one tension member interconnecting
each of said upwardly extending suspension frame members to said
frame of said fuselage so as to hold said frame from bowing
outwardly under loads exerted by said rack assembly; and at least
one lengthwise member that supports a plurality of cargo containers
arranged longitudinally on said rack assembly within said cargo
area in said upper lobe of said aircraft.
11. The apparatus of claim 10, wherein said at least one rigid
member mounted transversely across an upper end of said frame above
said storage area of said rack assembly comprises: at least one
rigid spreader bar member.
12. The apparatus of claim 10, wherein said at least one tension
member interconnecting each of said upwardly extending suspension
beam members to said frame of said fuselage comprises: at least one
flexible tension cable.
13. The apparatus of claim 10, wherein said locations on said
frames of said fuselage from which said rack assembly is suspended
comprise: pre-existing luggae bin attachment points on said frames
of said fuselage.
14. The apparatus of claim 10, wherein said at least one lengthwise
member that support said plurality of cargo containers arranged
longitudinally on said rack assembly comprises: at least one cargo
rail extending generally longitudinally across a plurality of said
lower frame members of a plurality of said rack frames.
15. The apparatus of claim 10, wherein said rack assembly further
comprises: at least one substantially horizontal panel member
mounted to said lower frame members of said plurality of rack
frames so as to form a shear panel for said rack assembly.
Description
BACKGROUND
a. Field of the Invention
The present invention relates generally to cargo systems for
aircraft, and, more particularly, to a system that enables
containerized cargo to be stowed in an upper, generally overhead
area of an upper lobe of a fuselage of an aircraft.
b. Related Art
For reasons of economy or flexibility, it is often desirable to
convert a passenger aircraft to transport cargo. Conversions may be
permanent or temporary/reversible, and moreover may involve the
entire aircraft or only a part of it. As a general rule, however,
it is desirable that such conversions be economical in nature, and
in particular that modifications to the existing air frame and
systems be kept to a minimum. Low weight is also a desirable
characteristic.
Another important factor is maximum utilization of available space.
In this regard, it will be understood that in the case of cargo
aircraft, volume rather than weight is often the limiting factor,
and so for efficient operation it is therefore generally important
to be able to fill as much as possible of the interior volume of
the fuselage with cargo.
Achieving the above goals is complicated by certain realities of
the aviation industry. First, it will be understood that in modern
operations most of the cargo is not packed "bulk" into the
fuselage, but instead is first placed into containers that are
loaded into the aircraft in a modular fashion. The containers
typically have configurations that are standardized (e.g., "LD6"),
at least by aircraft type, and generally have a somewhat
rectangular geometry, sometimes being angled or "beveled" at one or
both lower/outboard edges to better fit within the confines of the
cargo holds in the lower lobe.
As another factor, it will be understood that aircraft initially
configured for passenger use typically only have hatches capable of
receiving such containerized cargo in the lower lobe of the
fuselage, with access to the upper lobe/main deck of the aircraft
being limited to smaller doors designed primarily for passenger
ingress/egress and/or loading of in-flight service items. Adding
cargo-loading hatches to the upper lobe of an existing aircraft
generally requires modifications that would render such a
conversion unattractive from a cost standpoint, and furthermore the
ability to return the aircraft to a satisfactory passenger-carrying
configuration would be significantly compromised. Moreover, the
existing equipment of many airport facilities are designed primary
to load cargo through lower lobe hatches, rendering the advantages
of upper lobe cargo hatches moot.
One approach towards loading cargo into the upper lobe of an
aircraft while meeting the above constraints has been to employ a
lift mechanism that moves the containers from the lower lobe to the
upper lobe after they have been loaded into the latter, and
vice-versa during unloading. A non-limiting example is the lift
system that is shown in U.S. Pat. No. 8,011,617, which is
incorporated herein by reference. The structural modifications
involved in such an approach are mostly limited to the main deck of
the aircraft, to provide an opening for the cargo lift, and major
changes to the skin and frames of the fuselage are generally
avoided.
A remaining problem, however, has been that even after the cargo
containers have been loaded onto the upper, main deck of the
aircraft, much of the available space remains unfilled. It will be
appreciated that in passenger aircraft the main deck, which forms
the floor of the passenger compartment, is generally positioned
well below the mid-level of the fuselage, to provide adequate space
of the passengers and their luggage, as well as for various
overhead systems; consequently the height of the underlying cargo
compartments is typically much less than that of the passenger
compartment. As a result, since the height of the cargo containers
is necessarily constrained by the height of the cargo compartments,
the containers are insufficiently tall to fill the full height of
the passenger compartment when they are moved to the main deck, so
that an upper, overhead area of the fuselage remains unfilled. This
problem is particularly acute in the case of wide body aircraft
such as the Boeing B-777, with the result that a single height row
or rows of conventional containers will leave a great portion of
the upper lobe unfilled.
Accordingly, there exists a need for a system for carrying cargo in
an upper, overhead area of the upper lobe of the fuselage of an
aircraft, so as to make efficient use of available volume within
the fuselage. Furthermore, there exists a need for such a system
that allows the space in the upper portion of the upper lobe to be
filled with cargo in modular containers. Still further, there
exists a need for such a system in which such containers are loaded
into the aircraft through cargo doors providing access to one or
more cargo compartments in the lower lobe of the fuselage. Still
further, there exists a need for such a system that does not
require major modification of existing structures and systems of
the aircraft, particularly an aircraft previously configured for
passenger-carrying operation. Still further, there exists a need
for such a system that facilitates efficient performance of
functions by both flight crew and ground service personnel. Still
further, there exists a need for such a system that is light in
weight, and economical to construct and install.
SUMMARY OF THE INVENTION
The present invention addresses the problems cited above, and
provides a system for efficient handling and storage of
containerized cargo in an aircraft.
In a first aspect, the system provides an apparatus for carrying
cargo in an aircraft, the apparatus comprising a rack assembly
mounted in an upper part of a fuselage of the aircraft so as define
a cargo space in an upper lobe thereof, and means for supporting a
plurality of cargo containers arranged longitudinally on the rack
assembly within the cargo area in the upper lobe of the
aircraft.
The rack assembly may comprise a plurality of transverse rack
frames mounted at intervals to frames of the fuselage of the
aircraft. The transverse rack frames may each comprise a lower
frame member that extends substantially horizontally to form a
lower side of the cargo area in the upper lobe of the aircraft, and
first and second suspension frame members that extend generally
upwardly from the horizontal frame member towards locations on the
frame of the fuselage from which the rack assembly is suspended.
The means for supporting the plurality of cargo containers on the
rack assembly may comprise at least one cargo rail extending
generally longitudinally across the lower frame members of a
plurality of the rack frames.
The rack assembly may further comprise means for supporting the
upwardly extending suspension beams of the rack frames from
pre-existing luggage bin attachment points on the frame of the
fuselage. The means for supporting the upwardly extending beam
members from the pre-existing luggage bin attachment points may
comprise at least one pivotable link member interconnecting an
upper end of each of the suspension beam members to one of the
pre-existing attachment points on the frames of the fuselage. The
at least one pivotable link member may comprise a pivotable link
member aligned to transmit loads from the frame of the rack
assembly to the frame of the fuselage in a generally radial
direction. The geometry of the frames of the rack assembly and the
pivotable link members may be configured such that the pre-existing
bin attachment points are subjected by the rack assembly to load
vectors that are substantially similar to predetermined load
vectors for which the frames of the fuselage are rated with storage
bins mounted to the pre-existing attachment points.
The frames of the rack assembly may further comprise crossbeam
members mounted to the upper ends of the suspension beam members
and having upper and lower ends, the upper and lower ends of the
crossbeam members being attached by the pivotable link members to
the pre-existing attachment points on the frame member of the
fuselage.
The apparatus may further comprise at least one rigid bar mounted
transversely across an upper end of the frame of the fuselage above
the storage area of the rack assembly to hold the frame against
bowing inwardly under loads exerted by the rack assembly, and at
least one tension cable interconnecting each of the upwardly
extending suspension beam members to the frame of the fuselage so
as to hold the frame from bowing outwardly under loads exerted by
the rack assembly.
The rack assembly may extend substantially a full length of the
main fuselage section of the aircraft.
In another aspect, the invention provides a lift apparatus for
raising and lowering cargo containers between a main deck of an
aircraft and a storage area in an upper lobe of a fuselage of the
aircraft, comprising broadly a lift platform for supporting cargo
thereon, a lift mechanism for selectively raising and lowering the
lift platform between the main deck of the aircraft and the storage
area in the upper lobe of the fuselage, and a transverse barrier in
the fuselage having the lift mechanism mounted thereto so that
loads exerted by the lift platform on the lift mechanism are
supported by the barrier structure.
The lift mechanism may comprise a generally vertically aligned ball
screw assembly having the lift platform lifted to a traveling nut
portion thereof. In another embodiment, the lift mechanism may
comprise a telescopic hydraulic cylinder having the lift platform
mounted to an upper end portion thereof. Substantially an entirety
of the lift mechanism may be housed within the transverse barrier
structure.
The lift apparatus may further comprise at least one linear guide
mounted to the transverse barrier structure that stabilizes the
lift platform as the lift platform is raised and lowered by the
lift mechanism.
The lift platform of the lift apparatus may comprise a plurality of
deck members that nest between longitudinally extending fixed cargo
tracks on the main deck of the aircraft when the lift platform is
in the lowered position, the deck segments being substantially
level with the fixed cargo tracks when the lift platform is in the
lowered position so that cargo is able to transition horizontally
between the fixed rails and the lift platform of the lift
apparatus. The plurality of deck segments of the lift platform may
comprise substantially horizontal deck segments having cargo
rollers mounted thereon. In another embodiment, the deck segments
of the lift platform may comprise a plurality of substantially
horizontal tine members.
The transverse barrier structure to which the lift mechanism is
mounted may comprise a protective barrier installed between a
personnel area and a cargo area of the aircraft.
In another aspect, the invention provides a cover apparatus for
closing a cargo opening in a deck of an aircraft, the cover
apparatus comprising a plurality of substantially horizontal plate
members, and guide mechanisms supporting longitudinal edges of the
plate members from portions of seat tracks depending below said
main deck so that the plate members are selectively extensible
across said cargo opening.
The guide mechanisms may comprise linear guides mounting the edges
of the plate members to the depending portions of the seat
tracks.
The plurality of plate members of the cover apparatus may comprise
first and second sets of plate members that are selectively
extensible from opposite sides of the opening so as to meet
proximate a middle area thereof. The cover apparatus may further
comprise cooperating channel and tongue members mounted on opposing
distal ends of the first and second sets of plate members, that
meet to form a tongue-and-groove engagement that supports extended
ends of the plate members proximate the middle area of the
opening.
These and other features and advantages of the present invention
will be more fully appreciated from a reading of the following
detailed description with reference to the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevation view, partly in cutaway, of an exemplary
aircraft having an upper lobe cargo system in accordance with the
present invention installed therein;
FIG. 2 is an enlarged perspective view of the main fuselage section
of the aircraft of FIG. 1, with the skin of the fuselage removed
for clarity, showing the positioning the upper lobe cargo system
and also the arrangement of containerized cargo within the
fuselage;
FIG. 3 is a perspective, longitudinal cross-sectional view of the
aircraft fuselage of FIG. 2, without the cargo containers loaded
therein, showing the arrangement of the decks and the cargo
handling system therein in greater detail;
FIG. 4 is a perspective, transverse cross-sectional view of a
segment of the fuselage section of FIGS. 2-3, showing an exemplary
cargo container loaded on the upper lobe cargo rack of the system
of the present invention;
FIG. 5 is a second cross-sectional perspective view of the fuselage
segment of FIG. 4, showing a second container positioned on the
lower cargo deck in register with the opening in the main deck
through which containers are raised/lowered from/to the lower
level;
FIG. 6 is a transverse cross-sectional view of the fuselage segment
of FIGS. 4-5, showing the relationship of the upper lobe cargo rack
of the present invention and its supporting framework to the other
decks and to the structure of the fuselage in greater detail, and
also showing exemplary containers loaded on all three levels;
FIGS. 7A-7B are corresponding, comparative half-cross-sectional
views of the aircraft fuselage of FIG. 1 in the original
passenger-service configuration and after installation of the cargo
system of the present invention, respectively, showing the manner
in which pre-existing structure and attachment points of the
fuselage are employed for installation of the cargo system;
FIG. 8 is a transverse cross-sectional view of the fuselage segment
as in FIGS. 4-5, showing an upper load cargo rack in accordance
with another embodiment of the present invention;
FIG. 9 is a cutaway perspective view of the fuselage section of
FIG. 8, showing the structure of the upper lobe cargo rack thereof
in greater detail;
FIG. 10 is a cutaway plan view of the forward section of the
aircraft of FIG. 1, showing an exemplary barrier that is installed
between the cargo area and the main fuselage section and the
control and supernumerary spaces in the nose section of the
aircraft;
FIG. 11 is a perspective, cross-sectional view of a segment of the
main fuselage section of the aircraft of FIG. 1, looking towards
the forward end of the aircraft, showing the aft side of the
barrier shown in FIG. 10 and also the lift apparatus of the upper
lobe cargo system that is mounted thereto;
FIG. 12 is a second perspective, cross-sectional view of the
fuselage segment of FIG. 9, showing the positioning of containers
on and below the lift apparatus of the upper lobe cargo system
shown in FIG. 11;
FIG. 13 is a perspective, cross-sectional view of a segment of the
main fuselage section of the aircraft of FIG. 1, at an aft end
thereof and looking towards the forward end of the aircraft,
showing a second lift mechanism of the upper lobe cargo system of
the present invention that is mounted at an aft end of the upper
lobe cargo deck for raising/lowering containers to and from the
suspended upper rack;
FIG. 14 is a perspective view, similar to FIG. 11, of a fuselage
barrier incorporating a lift apparatus in accordance with a second
embodiment of the present invention;
FIG. 15 is a perspective view of the lift apparatus of FIG. 14,
separated from the barrier structure for purposes of
illustration;
FIG. 16 is a partial side elevational view of the lift apparatus of
FIG. 15, showing the relationship of the lift assembly and vertical
guides of the assembly in greater detail;
FIG. 17 is a top plan view of the barrier and lift apparatus of
FIG. 14, showing the manner in which the horizontal members forming
the deck of the lift assembly nest between the cargo rails of the
main deck of the aircraft.
FIG. 18 is an enlarged, partial perspective view of the barrier and
lift assembly of FIG. 14, with the platform of the lift assembly
lowered so as to be nested between the cargo rails of the main deck
of the aircraft as shown in FIG. 17, showing the platform edge gate
dropped down into a cooperating cutout formed in the rails of the
deck so as to allow passage of cargo containers onto/off of the
platform;
FIG. 19 is a perspective view of the barrier and lift apparatus of
FIGS. 14-18, showing the manner in which a cargo container is
raised/lowered on the platform of the apparatus;
FIG. 20 is a partial, perspective view of a fuselage section of the
aircraft of FIG. 1, showing a lift hole cover assembly in
accordance with the present invention, that is formed of a
plurality of plate members that are selectively extensible from
beneath the floor panels of the deck to cover the lift opening,
showing the cover assembly retracted to the open configuration;
FIG. 21 is a second partial, perspective view of the fuselage
section of FIG. 20, showing the lift hole cover assembly extended
to the closed configuration;
FIG. 22 is a upper perspective view of the main deck and the lift
hole cover assembly of fuselage section of FIG. 20, with the frames
of the fuselage removed for ease of illustration of the cover
assembly;
FIG. 23 is a lower perspective view of the deck and lift hole cover
assembly of FIG. 22, showing the relationship of the panels of the
cover assembly to the below-deck structure of the seat tracks in
greater detail;
FIG. 24 is an end view of one side of the aft edge of the lift hole
and associated cover assembly of FIGS. 20-23, showing the manner in
which the segments of the cover assembly are supported for
longitudinal movement from the below-deck side channels of the seat
tracks; and
FIG. 25 is a partial, side cross-sectional view of the distal edges
of opposing plate members of the cover assembly of FIGS. 20-24,
showing the cooperating tongue-and-groove structure that aids in
supporting the ends of the plate members when extended.
DETAILED DESCRIPTION
FIG. 1 shows an exemplary aircraft 10 having an upper lobe cargo
system in accordance with the present invention installed therein.
The example shows a wide body aircraft originally configured for
passenger service, specifically a Boeing B-777, however it will be
understood that the system may be installed in other suitable
models and types of aircraft. As is conventional, the aircraft
includes a main fuselage section 12, with a nose section 14 housing
control and supernumerary spaces at the forward end, an empennage
section 16 at the aft end, and a wing section 18 at an intermediate
location.
As can be seen with further reference to FIG. 1, and also FIG. 2,
the main fuselage section 12 includes an upper lobe 20 and lower
lobe 22, separated by the generally horizontal main deck 24. For
structural and operational reasons, the main fuselage section is
typically more-or-less cylindrical in shape over most of its
length, the lower lobe being interrupted by a wing box 26 to form
forward and aft cargo holds 30, 32; conventionally, the main shell
of the fuselage section is formed by a series of more-or-less
circular, rib-like frames or formers over which the skin is
mounted, the skin not being shown in FIG. 2. The upper lobe, in
turn, typically extends substantially the full length of the main
fuselage section, and forms the main passenger compartment in
aircraft that are configured for passenger service. Consequently,
as was discussed above and as can be seen in FIG. 1, access to the
upper lobe is typically via one or more comparatively small
passenger doors 34, while the fore and aft cargo areas are provided
with large cargo hatches 36a, 36b that are able to accommodate
containers far larger than could pass through the passenger door or
doors 34. The lower lobe may also include a smaller bulk cargo door
38, in the area of the lower lobe rearward of the aft containerized
cargo compartment.
Thus, standardized cargo containers 39 can be loaded into the lower
holds 30, 32 through hatches 36a, 36b in one or more rows, as
indicated at 40 in FIG. 1. A lift conversion, such as that noted
above, allows the containers to then be moved from the lower deck
or decks of the cargo areas to the main deck 24 of the former
passenger area in one or more rows, as indicated at 42 in FIG. 1.
Loading containers up to the main deck 24 alone, however, leaves
the uppermost (overhead) portion of the upper lobe unfilled: For
example, in an exemplary Boeing B-777 aircraft, some 18-20% of the
total volume of the main fuselage section may thus remain unfilled.
The present invention provides a system that enables this space to
be largely filled with additional containerized cargo, thus greatly
enhancing efficiency.
As can be seen in FIG. 2 and also FIGS. 3-6, the system of the
present invention provides a suspended rack 50 that is installed to
form a third level in the main fuselage section, on which
additional cargo containers can be placed in one or more rows so as
to fill the top portion of the upper lobe, as indicated at 44 in
FIG. 1. As can be seen in FIG. 4, the rack 50 is suitably
constructed of a series of transverse beams 54 and longitudinal
rails or tracks 56 underlain by a lightweight horizontal panel 52.
The rack 50 is supported by a trusswork 60, that is preferably
constructed of a series of lightweight rods, preferably arranged so
as to carry axial loads only. Upwardly and outwardly angled
suspension rods 62 are mounted to brackets 63 at the outer sides or
edges of rack 50, with the outer (distal) ends of the rods in turn
being mounted to pre-existing attachment fittings 64 formed on
frames 28 for supporting overhead stowage bins when the aircraft is
in a passenger configuration, the stowage bins having been removed
prior to installation of the overhead cargo system of the present
invention. The angular relationship of the suspension rods and
other geometry of the trusswork 60 is selected to maintain
substantially the same load vectors on the frames 28, through
attachment point 64, as that for which the frames were originally
rated with the overhead stowage bins installed. As can be seen in
FIGS. 7A-7B, which are comparative views of a fuselage section 12
"before-and-after" installation of the cargo system of the present
invention, the trusswork 60 supporting the overhead rack 50 mounts
to attachment points 64 that formerly supported the side and
centerline overhead storage bins 65a, 65b, the storage bins having
been removed for the conversion along with the passenger seating
66. Hence, the trusswork frame 60 enables the raised rack 50 to be
installed and used with the pre-existing frames and attachment
fittings, greatly enhancing the overall economy of the
installation.
As can be seen with further reference to FIG. 6, the trusswork 60
further includes side rods 68 that extend upwardly from attachment
brackets 66 at inward and upward angles to the suspension rods 62.
The upper ends of the side rods terminate closely adjacent the
inside surface of the fuselage section, proximate the inner edges
of the fuselage frames 28, where they may be mounted to additional
pre-existing bin attachment fittings, and where they are connected
to a horizontal upper rod 70 that extends parallel to rack 50 and
that spans the top of the trusswork frame 60. The side and upper
rods 68 and 70 thus cooperate with rack 50 to form a framework
having a generally quadrilateral cross-section and an open interior
passage 72. The horizontal lower panel 52, in turn, acts as a shear
panel to transfer fore-aft loads to the sides of the suspended
rack, where fore/aft aligned diagonal rods react the loads to the
fuselage shell, and also serves as a drip shield to channel liquid
into drains that run to the belly of the aircraft.
As can be seen in FIG. 6 and also FIGS. 4-5, the interior passage
72 defined by the quadrilateral framework is dimensioned to be able
to receive a standardized cargo container 74 of predetermined size.
In particular, the height between the rack 50 and top bar 70 is
designed to be just slightly higher than the predetermined height
of the containers 74, while the lateral spacing between the upper
ends of the side rods 68 as defined by top rod 70, is selected to
be just slightly greater than the predetermined width of the
containers, with sufficient clearance to allow the containers to
move longitudinally through the spaces 72. Since the corners
between the side rods 68a, 68b and top rods 70 are themselves
located closely adjacent the top inside surface of the fuselage,
the framework and deck hold the containers essentially as high in
the upper lobe of the fuselage as is possible given the width of
the containers; the lower side of the rack 50, in turn, is
positioned a height "h" (see FIG. 6) above the main deck 24 that is
sufficient to accommodate one or more rows of standardized
containers 80, sized for example to fit within the height of the
underlying cargo compartments. During flight the containers are
restrained by stops arid/or other fittings attached to the
longitudinal and/or lateral members 54, 56 of the suspended
rack.
A further advantage of the generally quadrilateral cross-section of
the trusswork frame 60 is to allow the system to be installed while
leaving clearance for preexisting or re-routed ventilation ducts
76a, 76b and other lines that are typically installed in the upper
sides of the fuselage section. Still further, the angle of the
suspension rods 62, upwardly and outwardly from the edges of rack
50, provides overhead clearance at the outboard sides of the
suspended rack 50, as indicated at 82 in FIG. 6, thus allowing
personnel 84 to walk the full length of main deck 24 without having
to stoop or hunch over.
FIGS. 8-9 illustrate an upper lobe suspended rack assembly 150 in
accordance with another embodiment of the present invention. As can
be seen, the storage area formed by the rack is somewhat similar in
cross-section to that of the embodiment illustrated in FIGS. 4-7
and similarly positions the containers close to the crown of the
fuselage, however, the structure and the manner in which loads are
distributed into the fuselage are somewhat different in the
embodiment shown in FIGS. 8-9.
As can be seen in FIGS. 8-9, the rack assembly 50 is constructed of
a series of somewhat U-shaped frames 152, preferably mounted at
each fuselage frame 28 over the length of the fuselage in which the
rack assembly is installed. Each rack frame 152 includes a
crossbeam 154 that extends horizontally across the fuselage when
the frame is installed, with a suspension beam 156 extending at an
upward and outward angle (e.g., approximately 70.degree. to
horizontal) at each end. Spreader or crossbeams 158 are in turn
mounted to the upper, outboard ends of the upwardly extending
suspension beams, in a somewhat T-shaped configuration. The angle
in which the spreader beams 158 are mounted to the suspension beams
is selected such that the two ends of the spreader beams extend
upwardly-inwardly and downwardly-outwardly from the suspension
beams to locations that are positioned generally proximate each
fuselage frame 28; in the preferred embodiment that is illustrated,
the upper ends of the spreader beams extend at an upward and inward
angle of about 120.degree. to the suspension beams, while the lower
ends extend at a downward and outward angle of about 60.degree.. It
will be understood that angles may vary somewhat depending on rack
size, fuselage configuration, attachment point locations and other
design factors, and that the foregoing angles are therefore given
by way of example rather than limitation.
The two ends of each spreader beam 158 are connected to the same
frame 28 on opposite sides of the fuselage, preferably utilizing
pre-existing overhead bin attachment points as discussed above. The
outboard/lower ends of the spreader beams are supported from the
frame 28 by relatively short rod members 160 having yokes 162 at
their upper ends that are pivotably pinned to the fuselage frame,
and brackets 164 at their lower ends that are pivotably connected
to the ends of the spreader beams. The spreader beams and
connection points are preferably dimensioned and located so that
the lower/outer rods 160 are aligned generally vertically as shown
in FIG. 8 and therefore loaded primarily in tension to support the
weight of the rack and the cargo carried thereon. The upper/inboard
ends of the spreader beams are similarly connected to attachment
points on the fuselage frame 28 by means of comparatively short rod
members 166 pivotably mounted to the frame and the beam ends by
yokes 162 and brackets 164, but preferably at a more inwardly
directed angle (e.g., approximately 45.degree.) to both support the
rack/cargo and stabilize it against lateral movement. The angles of
the rods and their locations also serve to mimic the types and
directions of loads exerted by the overhead bins for which the
attachment points were originally selected and engineered,
facilitating both engineering and load calculations for the rack
assembly and also potentially simplifying certification issues.
The beam members 154, 156, 158, which are suitably formed of
aluminum alloy, fiber composite or other material having suitable
strength and weight characteristics, and that are joined by
fasteners, welding, adhesives, co-molding or other means suitable
to the material, thus form rigid frame elements 152 that are
suspended from the fuselage frames from the rod members 160, 166.
As can be seen in FIG. 9, a series of the frame members 152 are
mounted in a substantially identical manner to the fuselage frames
28 over a length of the fuselage in which the upper lobe cargo rack
is installed. In the embodiment that is illustrated, the rack
frames 152 are mounted at each fuselage frame 28 over the length of
the installation, enhancing the strength and load carrying capacity
of the rack system; in those instances where the fuselage being
converted does not include pre-existing mounting points for
overhead bins at each frame 28 (e.g., where the mounting points are
provided at every other frame), corresponding attachment points can
be formed on the intermediate frames using a jig or other suitable
mechanism. Similar to the embodiment described above, a panel or
series of panels 168 is mounted to the lower, horizontal beam
members 154 of the frames over the length of the rack to form an
integrated assembly, both for purposes of rigidity and strength and
to prevent excessive fore-aft movement of the assembly.
Longitudinal roller tracks 170 are in turn installed over the tops
of the horizontal beams 154 to support movement of containers
thereover in a manner also similar to the embodiment described
above.
Installed in the manner described above, the rack assembly thus
forms an upper lobe cargo area 172 that supports the load of cargo
containers 174 at a level above the containers 176 on the main deck
24 of the aircraft. Thus, similar to the embodiment described
above, the rack system 150 greatly improves utilization of volume
available within the fuselage.
It has been found that the loadings made possible by the rack
assembly may in some instances have the potential to create
deformation or "bowing" of the upper fuselage under some
circumstances. In particular, application of the inward/downward
loads of the loaded rack assembly to the upper sides of the
fuselage may potentially cause the frames 28 and surrounding shell
of the fuselage to bend inwardly somewhat at the sides and bulge
upwardly somewhat at the crown.
In order to obviate the foregoing possibility, the rack
installation 150 further includes a series of rigid, fixed length
spanner bars 180 that are mounted horizontally across the fuselage
frames 28 using links 182, above the upper load cargo space 172
formed by the rack assembly, and preferably in accompaniment with
each rack frame 152. Cables 184 in turn extend at outward and
downward angles from the approximate midpoints 186 of the
suspension beams 156 of the rack frames 152, to links 188 mounted
lower down on the sides of the fuselage but still high enough to
provide clearance for the containers 176 on the main deck 24. With
links 182 and 188 suitably adjusted, the spanner bar resists inner
loads on the fuselage frame 28 in compression while the cables 184
resist outward loads in tension, thus maintaining the generally
circular form of the frames 28 and thereby avoiding inward/outward
bowing of the upper fuselage due to the loads carried on the upper
lobe rack.
In order to raise containers 74 from main deck 24 to the suspended
rack 50, forward and aft lift assemblies 90, 92 are located at
opposite ends of the fuselage section 12. As can be better seen in
FIGS. 11 and 13, each of the lift mechanisms 90, 92 in the
embodiment illustrated therein includes a lift fork assembly 94
made up of a series of projecting, longitudinally extending tines
96 supported on a triangular frame constructed of a horizontal bar
98, a vertical center post 100, and angled bars 102a, 102b that
connect the ends of the main horizontal bar 98 to the top of the
center post 100. The forks 94 are sized to fit under the containers
74 over substantially all or most of the length thereof, while the
framework 94 provides rigidity and support to the tines while
raising/lowering the containers.
As can be seen with further reference to FIGS. 11 and 13, an
upwardly gusseted bracket 104 is mounted at the base end of each of
the fork tines 96. Paired rollers 108 (shown in phantom in FIG. 13)
are mounted on the ends of brackets 104 opposite the tines and are
captured for vertical rolling movement in stanchions 110, each of
the stanchions being formed by a pair of parallel, inwardly facing
C-section channel members 112 that are sized to receive rollers 108
in rolling engagement therewith. The adjoining channel members of
each stanchion are spaced apart slightly to form a slot 114 sized
to accommodate the cooperating bracket 104, so as to permit the
latter to move freely along the stanchion while retaining the
paired rollers therein.
The stanchions 110 thus provide support for the fork assembly 94 of
each lift mechanism, while allowing the fork assembly to move in
upward and downward directions. The center post 100 of the fork
assembly, in turn, is mounted to the upper segment 118 of a
telescopic hydraulic cylinder 120, the lower end of which is
mounted to the main deck 24 of the fuselage. Hydraulic power is
supplied to the telescopic cylinder by a motor (not shown) and
fluid reservoir 122, to selectively move the fork assembly between
a lowered position in which the tines 96 are substantially level
with tracks 124 in main deck 24 (where they nest between existing
roller trays) and a raised position in which the tines are
substantially level with corresponding tracks 56 in the suspended
rack 50, the tines including roller and the ends of the tines
preferably being beveled somewhat to ease in transitioning
containers between the rails and the tines.
As can be seen with further reference to FIG. 11 and also FIG. 10,
the forward lift mechanism 90, and in particular the stanchions 110
thereof, are preferably mounted to the aft side of a bulkhead
structure 130 that is mounted at the forward end of fuselage
section 12, proximate the juncture between it and the nose section
14: The bulkhead 130, which may be of a type referred to as "9G
Bulkhead," is manditorily installed in aircraft configured for
cargo transport operations, and is intended to protect the control
and supernumerary spaces 132, 134 in the nose section from cargo
shifting forward in the event of a hard landing or other accident.
Bulkhead 130 is therefore usually a relatively sturdy structure,
and utilizing it as an attachment/support for the forward lift
mechanism enhances both structural and space efficiency.
Furthermore, as can also be seen in FIG. 10, the bulkhead 130 may
include doorways 136a, 136b that communicate with the cargo
compartment in the main fuselage section, through which personnel
may enter to walk on either side of the cargo in the manner shown
in FIG. 6.
Accordingly, to fully load the aircraft with containers, as shown
in FIG. 1, the first containers 74 are loaded into the forward
and/or rearward cargo holds 30, 32, through hatches 36a, 36b, and
moved along rails 86 over the lower deck 88 into position beneath
one or more lift openings 140 in the main deck 24, as shown in FIG.
5. The lift mechanism at opening 90 may suitably be of the kind
which is disclosed in the above-identified copending application,
although it will be understood that other forms of lift mechanisms
may be used. In the illustrated embodiment the lift deck
selectively moves between the level of the lower cargo deck 88 and
main deck 24, and is stowed in the raised position with the deck
142 (see FIG. 3) being latched to cooperating structures 144 at the
edges of the opening.
Thus, during loading, the lower deck lift mechanism raises the
containers from the cargo compartment or compartments 30, 32 to the
main deck 24, over which the containers are then moved along
cooperating rails 124 until positioned over the tines 96 of the
fork assembly of the forward and/or aft lift assembly 90, 92. The
containers are then raised until level with the suspended rack
assembly, and then transitioned off of the fork tines and onto the
rails 56 of the suspended deck, over which they are moved
longitudinally so as to fill the suspended deck to the extent
desired with the upper row 44 of containers. Subsequently or
simultaneously, additional containers are fed into the cargo holds
and lifted to the main deck through openings 140 by the lower lift
mechanism, so as to fill to the desired extent the main deck with
the middle row 42 of containers. Additional containers 146 are then
loaded into one or both of the lower cargo compartments and moved
along rails 86 into position to fill the compartments to the extent
desired with the lowermost rows 40 of containers, so that
ultimately substantially all of the available volume in the
fuselage section is filled with containers. Unloading can be
performed in a substantially reverse sequence.
FIGS. 14-19 illustrate a lift apparatus 190 in accordance with
another embodiment of the present invention, that serves to
raise/lower cargo to/from the upper lobe storage area similar to
the embodiment shown in FIGS. 11-12, and which among other aspects
features further incorporation of the mechanism into the adjoining
bulkhead, e.g., the 9G Bulkhead separating the cargo and
controls/supernumerary spaces. As noted above, a 9G Bulkhead (or
equivalent) is required in cargo conversions in general,
consequently incorporating the lift apparatus into the bulkhead so
that the bulkhead serves both as a barrier and as a combined
enclosure and support for the lift mechanism represents a
significant savings in terms of weight and space. It will be
understood that the term "9G Barrier" as used in this description
and the appended claims includes all such barriers installed
between cargo and personnel spaces, whether rated for "9G" loads or
a higher or lower specifications.
As can be seen in FIG. 14, the barrier 192 of the illustrated
embodiment is constructed in four sections, namely, a pair of
upward sections 194a, 194b, suitably including cutout areas 196 for
doors/personnel passages, and inboard sections 198a, 198b that meet
generally at the centerline of the fuselage. By constructing the
barrier in four sections as shown, it is possible to size the
sections to fit through existing openings in a passenger configured
aircraft, either through the passenger/service access doors of the
main deck or through the cargo doors of the lower deck, thus
greatly facilitating installation.
The lift apparatus 190 includes a series of upright supports/guides
that are mounted at the vertical junctions between the sections of
barrier 192. As can be seen in FIG. 15, which shows the lift
mechanism with the sections of the barrier removed, the vertical
guides/supports are formed by a series of linear guide rods, a
first set 202a-b being mounted at the vertical junctions between
the outward panels 194a-b and inboard panels 198a-b, and a second
set 204a-b being mounted as a pair at the centerline junction
between the inboard barrier sections 198a-b. The linear guide rods
202a-b and 204a-b are "off-the-shelf" items available from numerous
suppliers, and are supported over their lengths by the structure of
barrier 192, which will be described in greater detail below. The
platform 200 of the assembly includes guide collars 206 mounted in
upper and lower pairs, that engage each of the linear guide rods
for vertical movement thereon. A ball nut assembly 210 vertically
mounted at the junction between the inboard barrier sections
298a-b, at a centerline position intermediate the inboard pair of
linear guides 204a-b, drives the lift platform 206
upwardly/downwardly by means of a traveling nut unit 212 on a
threaded shaft 214 rotated by an electric servo motor 216 and
supported in an end bearing 218, the whole being mounted on a frame
plate 220, that is in turn mounted to the adjoining bulkhead
sections 198a-b. Suitable ball screw assemblies are again available
from several suppliers known to those skilled in the relevant
art.
As can be seen with further reference to FIG. 15, and also to FIG.
16, the collars 206 that receive the linear guides are mounted in
vertical pairs to upper and lower horizontal, transverse frame
members 222, 224 of the lift platform 200. The upper and lower
horizontal members are joined by vertical frame members 226, so as
to react loads inwardly and outwardly directed loads onto the
linear guides and from there into the structure of the barrier.
Horizontal frame members 228 extend from the lower ends of the
vertical frame members 226 to form the edges of the deck of the
lift platform, the joint between the vertical and horizontal frame
members being strengthened by gusset plates 230. Angled brace rods
232 in turn extend between the upper ends of the vertical frame
members 226 and the distal ends of the horizontal frame members
228, the joint between the angled braces and the former again being
strengthened by gusset plates 234.
The distal ends of the two side frame members 228 are joined by a
second transverse horizontal frame member 236 that extends
generally parallel to the first horizontal frame member 224 and
forms the edge of the deck of the lift platform 206. The deck
itself is defined by a series of comparatively wide roller deck
segments 238 that, as will be described in greater detail below,
nest between the fixed tracks of the main deck of the aircraft for
transfer of cargo onto and off of the deck of the lift platform.
The angled stay members 232 thus cooperate with the horizontal
frame members 228, 236 and 224 to support the elements of the deck
under the loads of the containers/cargo carried thereon. The
platform assembly is preferably further strengthened by a shear
panel (not shown for ease of illustration) mounted over the
vertical and horizontal members 226, 222, 224 at the back of the
lift platform.
As noted above, and as can better be seen in FIGS. 17-18, the
roller deck segments 238 of the deck of the lift platform nest
between and are level with the fixed cargo tracks 240 on the main
deck of the aircraft when the platform is in the lowered position.
Additional horizontal deck segments 242 including cargo rollers are
mounted intermediate the rail segments 238 so as to nest on the
main deck 24 in the areas 244 between tracks 240.
As can be seen in FIG. 18, when the lift platform 200 is in the
lowered position the transverse, horizontal frame bar 246 at the
front of the platform is received in a series of cooperating
cutouts 248 formed in the upper edges of the main deck cargo rails
240. The cutouts 248 also accommodate a gate member 250 that is
mounted along the distal edge of the front frame member 246 on
hinges 252 so that the gate lies substantially flat therein when
lowered, as shown in FIG. 18. With the forward edge of the platform
in this position and configuration cargo containers/pallets are
able to transition freely from the fixed rails 240 of the aircraft
deck onto the horizontal roller segments 238, 242 that define the
deck of the lift platform, and visa versa, the length of the
cutouts 248 being no greater than the standardized spacing between
the roller 249 (e.g., 10 inches) of the fixed tracks 240, so that
the container/platforms remain fully and evenly supported when
passing thereover. Then, when the gate 250 is raised, it acts as a
barrier against the containers/pallets inadvertently rolling off of
the lift platform while the latter is being raised/lowered; a
raised stop 254 along the back of the gate member (see also FIG.
16) cooperates with the ends of the deck roller segments to arrest
the gate in the vertical orientation, with the gate then being held
in place by a pin, catch or other latching suitable mechanism.
Also, in combination with the horizontal frame member 246, the gate
member when raised forms the vertical flange of an L-shaped (in
cross-section) piece across the front of the lift platform, that
imparts additional rigidity and strength against forces tending to
bend/twist the lift deck, e.g., due to off-center loads.
Thus, as is shown in FIG. 19, lift assembly 190 provides a rigid,
well stabilized structure for raising and lowering cargo, such as a
container 174, to and from an upper lobe storage area in an
efficient and safe manner, as indicated by arrow 256. Moreover,
since the drive and guide components of the assembly are housed
within the interior of the barrier 192 cargo containers/pallets on
the main deck can be loaded fully up to the rearward side of the
bulkhead, consequently there is no loss of interior volume/capacity
owing to the lift mechanism. Furthermore, the final
container/pallet raised to the upper level can remain safely in
place on the deck of the lift platform during flight, thus
maximizing usage of the upper lobe volume as well.
As was noted with the embodiment described above, the lift
mechanism of the embodiment shown in FIGS. 14-19 may be employed in
conjunction with upper lobe storage racks as disclosed herein, or
may be used with other types of storage structures as well.
FIGS. 19 and 17 also show in greater detail the internal structure
of the bulkhead 192 of the illustrated embodiment. As can be seen
therein, each of the bulkhead sections 194a-b and 198a-b is formed
of forward and aft panels 260, 262 mounted to the flanges of
vertical beams 264 so as to form a rigid, lightweight structure,
the upper edges of the panels being curved to follow the interior
contour of the fuselage and the lower edges of being generally
straight to conform to the main deck. The beams carry shear loads
vertically into the structure of the aircraft, allowing the panels
and core of the barrier to be constructed using lighter weight
material. The spaces between the panels 260, 262 and intermediate
the beams 264 are preferably filled with a lightweight material
(e.g., lightweight aluminum honeycomb) which for ease of
illustration is not shown.
Additional vertical beams 264 are mounted at the junctions between
the outboard and inboard panels 194a-198a and 194b-198b, with the
vertical guides 202a-b being mounted to the aft edges thereof. The
primary loads of the lift mechanism are therefore transmitted to
beams 266, and from there to the fuselage/deck, as well as somewhat
through the beams and panels of the adjoining bulkhead segments.
The secondary vertical guides 204a-b of the ball screw assembly are
located proximate the edges of a gap 266 formed between the panels
262 of the inboard barrier segments 198a-b, where the latter meet
proximate the centerline of the aircraft with vertical beams
flanking the ball screw assembly, accommodating vertical movement
of the connection between the traveling nut of the ball screw
assembly and the platform 200 of the lift apparatus.
The bulkhead structure described above provides significant
advantages in terms of low weight and effective transmission of
loads from the lift mechanism into the body of the aircraft,
however, it will be understood that the lift mechanism may also be
used with forms of bulkhead construction in addition to that which
is shown, e.g., with bulkheads having other types of cores.
As noted above, in the illustrated embodiment the platform 142 of
the lower deck lift mechanism stows in a raised position, level
with the main deck 24 of the fuselage (see FIG. 3). When lowered,
however, in the course of shifting containers or for other
purposes, the opening 140 remains exposed, presenting a hole
through the deck that is a hazard to personnel moving fore-aft
through the fuselage. In order to overcome this problem, the
present invention provides a retractable cover assembly that
extends into the opening 140 in order to permit personnel to safely
transit between the adjoining forward and aft sections of the main
deck.
As can be seen in FIGS. 20-23, the cover assembly 270 is made up of
a plurality of substantially parallel, longitudinally extending
plate members 272, 274. Each of the plate members 272, 274 in the
illustrated embodiment has a length approximately equal to or
greater than one-half the fore-aft dimension of the opening 270, so
that when longitudinally extended the combined span fully covers
the opening as shown in FIG. 21. Each of the panel members
comprises an elongate, generally rectangular panel, suitably
constructed of a corrugated alloy or composite sheet sandwiched
between horizontal upper and lower panels to give adequate
strength/rigidity to support the weight of one or more
personnel.
As can be seen with further reference to FIGS. 23 and 24, the edges
of the plate members 270, 272 are supported in rolling engagement
with cooperating portions of preexisting longitudinally extending
seat tracks 276. The extending seat tracks are installed in the
main deck of the fuselage section as part of the original passenger
configuration, and as can be seen in FIG. 24 they include upwardly
facing channel portions 278 that receive cooperating flange
portions (not shown) on the seats, that allow the latter to be
mounted at the desired pitch. As is characteristic, for example, in
a Boeing B-777, the depending portions of the seat tracks 276
further include outwardly facing lower channel portions 280a, 280b,
defined by horizontal upper flange portions 282 in conjunction with
horizontal lower flange portions 284 having raised outer lips. As
can be seen in FIG. 24, the edges of rigid floor panels 286 rest on
and are supported by the horizontal upper flanges 282 of the seat
tracks, with the panels 286 spanning the gaps between adjoining
seat tracks 274 to form the floor of the main deck 24.
The edges of the plate members 272, 274 are in turn supported from
the underfloor portions of the seat tracks 276, by guides that
allow the plate member to be selectively extended/retracted in a
linear direction. For example, in the preferred embodiment that is
illustrated, the edges of the plate members may be supported by
ball-bearing linear guides, similar in operation to drawer slides,
mounted to the depending sides of the seat tracks. In another
example, the plate members may be supported by rollers along the
longitudinal edges of the plate members that are received in the
lower, generally C-shaped channels 280a, 280b of the seat tracks,
the wheels of the rollers being spaced outwardly from the
longitudinal edges of the plate members on horizontal axles to form
gaps that accommodate the upturned lips of the lower flanges and
the rollers having a diameter sized just slightly less than the
height between the horizontal flanges 282, 284 so as to form a
rolling engagement with the channels.
The plate members 272, 274 of the cover are thus supported parallel
to and immediately below the floor panels 286, above the transverse
beams 290 of the main deck 24 and over the underlying cargo
compartments. The first set of the plate members 272 is installed
between adjoining seat tracks at the forward edge of the main deck
opening 140, while the corresponding set of plate members 274 is
installed between the seat tracks at the rearward edge 186.
Thus mounted, the plate members 272, 274 are selectively extensible
into and retractable from the opening 140, in the directions
indicated by double-ended arrow 292 in FIG. 22. When extended, the
panel members are supported in a cantilever manner by the roller
guides at their base ends from the seat rail channels 276. In
addition, as can be seen in FIG. 25, the distal ends of opposing
pairs of the plate members 272, 274 include horizontally aligned
channel pieces 294 and cooperating tongue pieces 296, that interfit
in a tongue-and-groove manner when the plate members meet proximate
the middle of the opening to provide additional rigidity and help
to hold the extended panel members flat under the weight of a
person thereover. The channel and tongue pieces may be mounted to
the plate members 272, 274 individually, or they may be elongate
pieces mounted across the ends of their respective sets of plate
members so as to join the sets of plate members together for
movement as a single unit.
Accordingly, when both sets of panel members are extended to meet
at the middle of the opening, as shown in FIG. 21, they form a
continuous, substantially rigid cover over which personnel can
safely pass. Then, when desired, the panel members can be retracted
into their respective edges of opening 140, to permit the lift to
raise/lower containers therethrough and to also be stowed therein,
as described above. Extension and retraction can be performed
manually, or for example by a suitable hydraulically- or
electrically-operated mechanism, such as a power drive unit (PDU)
for example.
It is to be recognized that various alterations, modifications,
and/or additions may be introduced into the constructions and
arrangements of parts described above without departing from the
spirit or ambit of the present invention.
* * * * *